JPH0453394A - Cabinet for speaker - Google Patents

Abstract

PURPOSE:To obtain a speaker cabinet in which high stiffness and a large internal loss are made compatible by using a composite of liquid crystal high polymer fibers and thermoplastic synthetic resin fibers. CONSTITUTION:Liquid crystal high polymer fibers are bound and made composite with molten thermoplastic synthetic resin fibers at heat forming. As the liquid crystal high polymer fibers, ethylene co-polyester made of parahydroxyne benzoic acid and telephthale acid or co-polyester made of phenylene and biphenylene or the like are employed. Then high stiffness and a large internal loss (tandelta) are obtained and since the two kinds of fibers are almost in mixture, the forming time is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cabinet used in a speaker device.

[Prior Art] As is well known, a speaker cabinet holds a speaker in a manner suitable for use, and also acoustically isolates the space in front of and behind the speaker diaphragm, thereby reducing the influence of anti-phase sound waves emitted from the back of the diaphragm. It has the effect of preventing this, increasing the acoustic radiation efficiency, and further improving the frequency characteristics of the speaker device by providing an acoustic circuit such as a duct. Speaker cabinets that have this type of action may vibrate due to the internal sound pressure and the reaction force of the speaker drive system, emitting unnecessary sound waves and deteriorating the quality of reproduced sound. In order to prevent the negative effects of self-vibration, the cabinet constituent material is required to have as much rigidity as possible and a large vibration absorbing force to suppress abnormal resonance of the diaphragm.

The typical structure of conventional cabinets is, for example (
1) Items made of a single material such as wood, metal, or synthetic resin;
(2) A mixture of fillers such as wood or carbon fiber with a thermosetting resin and heat molding, and (3) A mixture of the above filler and a thermoplastic synthetic resin and heat molding have been put into practical use. There is.

[Problem to be solved] Conventional cabinets with such a structure have difficulty achieving both rigidity and vibration absorption power for cabinets belonging to (1) due to the properties of the material, and cabinets belonging to (2) have difficulty achieving both rigidity and vibration absorption power. Since the binder of the filler is a thermosetting resin, it has low impact resistance, low water resistance, and low long-term stability. Furthermore, products whose molding cycle during production is long and whose molding raw material is in the form of prepreg do not have good storage stability. Furthermore, when a cabinet belonging to category (3) is made of, for example, polypropylene resin as the thermoplastic synthetic resin, the drape during molding is poor and high-pressure pressing is required, which is a problem to be solved.

Therefore, the present invention solves the problems of the above-mentioned conventional examples by using a composite of liquid crystalline polymer fibers and thermoplastic synthetic resin fibers, and achieves both high rigidity and large internal loss in a speaker cabinet. The purpose is to provide

[Means for Solving the Problems] A speaker cabinet according to the present invention for achieving the above object is made of liquid crystalline polymer fibers and thermoplastic synthetic resin fibers, and the liquid crystalline polymer fibers are heated This speaker cabinet is characterized in that it is bonded and composited with thermoplastic synthetic resin fibers that are melted during molding.

[Function] Liquid crystalline polymer fibers have a lower density (ρ) and higher cutting strength (1.5 to 2 times that of carbon fibers, etc.) than conventional composite materials such as carbon fibers. It is thermally stable as it has a high melting point of over 300℃, and since it is a fiber with a fibrillar structure, the internal loss (tan δ) of the fiber itself is reduced.
) is characterized by a large value.

By compounding liquid crystalline polymer fibers with such properties with molten thermoplastic synthetic resin fibers, the liquid crystalline polymer fibers are uniformly dispersed in the composite material, and the physical properties of the composite material are better than those of conventional materials. Compared to a composite material using carbon fiber or the like, ρ is smaller and tan δ is larger. Furthermore, since both fibers are thermoplastic synthetic resin fibers, they have excellent impact resistance and storage stability, and since the two types of fibers are in close contact with each other, the molding time can be shortened. Furthermore, compared to conventional sheet-shaped thermoplastic synthetic resin composites, it has excellent drapeability and wettability, resulting in no voids and stable quality.

[Example] A plain woven fabric of wholly aromatic polyester fiber was used as the liquid crystal polymer fiber, and a plain woven fabric of PP (polypropylene resin...glass transition temperature -0°C, melting point 170°C) fiber was used as the thermoplastic synthetic resin fiber. A plain woven fabric made of PP fibers was alternately layered on both sides of a plain woven fabric made of fully aromatic polyester fibers to make a total of 10 layers, and the temperature was gradually raised at a press pressure of 10 kg/al.
Press pressure 0-3 Q K g/a for about 15 minutes at ℃
After degassing the air in the fibers by moving the fibers up and down, the temperature was raised to 140°C with a press pressure of 30Kg/cnf, and after holding for 5 minutes,
A flat composite material was prepared by cooling to 100° C. on a mold, and this composite material was cut and bonded to obtain a speaker cabinet. tan of the cabinet at room temperature
The values of δ, Young's modulus E1 density ρ, and E/ρ are shown in Table 1. For comparison, the above physical property values of a conventional cabinet obtained by laminating carbon fiber woven fabric and epoxy resin prepreg are also shown. From this result, the composite cabinet of the present invention exhibits higher elasticity and larger tan δ than the conventional example because the liquid crystalline polymer fiber itself has a larger internal loss than the conventional carbon fiber.

The values of tan δ, Young's modulus E1 density ρ, and E/ρ of the cabinet at room temperature are shown in Table 1, and the molding conditions are shown in Table 2. For comparison, the above physical property values of a conventional cabinet obtained by laminating carbon fiber woven fabric and epoxy resin are also shown. These results show that the composite cabinet of the present invention has high rigidity and a large tan δ compared to the conventional example. In particular, regarding the molding time, the pressure may be about 1/2 that of the conventional epoxy resin prepreg because the thermoplastic synthetic resin fibers melt easily.

Table 1: E: Young's modulus ρ: Density unit...dyn e/crl...
...gr/am 3 Table 2 As a means for obtaining the composite of the present invention, as a modification 1 of the above embodiment, a long fiber strip (comin It can also be obtained by stacking one layer or a plurality of layers of woven fabric (cross-over weave, triaxial weave, disc weave, etc.) made of (glued yarn). In addition, as a second modification, one layer or a plurality of layers of a woven fabric of a bride matrix in which the surface of liquid crystalline polymer fibers is wrapped with thermoplastic synthetic resin fibers may be stacked and molded. Alternatively, as a third modification, it is possible to use a woven fabric made by interweaving two types of fibers.

Above, the speaker cabinet according to the present invention has been described in detail based on embodiments that are considered to be representative, but the embodiments of the cabinet according to the present invention are limited to the structure of the above embodiments in terms of the material of the resin material, etc. However, the present invention may be modified and implemented as appropriate, as long as it has the constituent features recited in the claims, exhibits the functions of the present invention, and has the effects described below.

[Effects] In the speaker cabinet according to the present invention, liquid crystalline polymer fibers are melt-bonded and composited with thermoplastic synthetic resin fibers, and the density of the liquid crystalline polymer fibers is approximately lower than that of carbon fibers. 172, is small and lightweight, and has a melting point of 30
It is thermally stable because it is as high as 0°C or higher, and furthermore, because it is a fiber with a fibrillar structure, it has a characteristic that the internal loss (4anδ) of the fiber itself is large.

By combining liquid crystalline polymer fibers with such properties with molten thermoplastic synthetic resin fibers, the liquid crystalline polymer fibers are uniformly dispersed in the composite material, and the physical properties of the composite material are similar to those of conventional carbon fibers. ρ is smaller compared to composite materials using
The tan δ becomes large.

In addition, since thermoplastic synthetic resin fibers are used, it has excellent impact resistance, water resistance, long-term stability, and storage stability.
Since the different types of fibers are in a semi-mixed state, the molding time can be shortened. Furthermore, compared to conventional sheet-shaped thermoplastic synthetic resin composites, it has excellent drapability and wettability, so it has the effect of being free of voids and having stable quality.

Patent applicant: Onkyo Corporation

Claims (2)

[Claims] (1) A speaker comprising liquid crystalline polymer fibers and thermoplastic synthetic resin fibers, wherein the liquid crystalline polymer fibers are bonded and composited by thermoplastic synthetic resin fibers melted during heat molding. cabinet for (2) The speaker cabinet according to claim 1, wherein the liquid crystalline polymer fiber is an ethylene copolyester consisting of parahydroxybenzoic acid and terephthalic acid, or a phenylene or biphenylene copolyester.